package com.zbangmall.util.algorithm;


import com.zbangmall.util.common.CharsetUtil;
import com.zbangmall.util.common.SysUtil;

import java.io.UnsupportedEncodingException;

/**
 * 对比俩个字符串的相似度
 */
public class StringImpl {
	//第一种实现方式
	private static String longestCommonSubstring(String strA, String strB) {
		char[]  chars_strA = strA.toCharArray();
		char[]  chars_strB = strB.toCharArray();
		int     m          = chars_strA.length;
		int     n          = chars_strB.length;
		int[][] matrix     = new int[m + 1][n + 1];
		for (int i = 1; i <= m; i++) {
			for (int j = 1; j <= n; j++) {
				if (chars_strA[i - 1] == chars_strB[j - 1]) {
					matrix[i][j] = matrix[i - 1][j - 1] + 1;
				} else {
					matrix[i][j] = Math.max(matrix[i][j - 1], matrix[i - 1][j]);
				}
			}
		}
		char[] result       = new char[matrix[m][n]];
		int    currentIndex = result.length - 1;
		while (matrix[m][n] != 0) {
			if (matrix[n] == matrix[n - 1]) {
				n--;
			} else if (matrix[m][n] == matrix[m - 1][n]) {
				m--;
			} else {
				result[currentIndex] = chars_strA[m - 1];
				currentIndex--;
				n--;
				m--;
			}
		}
		return new String(result);
	}

	private static boolean charReg(char charValue) {
		return (charValue >= 0x4E00 && charValue <= 0X9FA5) || (charValue >= 'a' && charValue <= 'z') || (charValue >= 'A' && charValue <= 'Z') || (charValue >= '0' && charValue <= '9');
	}

	private static String removeSign(String str) {
		StringBuffer sb = new StringBuffer();
		for (char item : str.toCharArray()) {
			if (charReg(item)) {
				sb.append(item);
			}
		}
		return sb.toString();
	}

	/**
	 * 快速比较俩个字符串的相似度
	 *
	 * @param strA 较长的字符串
	 * @param strB 较短的字符串
	 * @return 俩个字符串的相似度
	 * <p>summary</p>:较长的字符串放到前面有助于提交效率
	 */
	public static double SimilarDegree(String strA, String strB) {
		String newStrA = removeSign(strA);
		String newStrB = removeSign(strB);
		int    temp    = Math.max(newStrA.length(), newStrB.length());
		int    temp2   = longestCommonSubstring(newStrA, newStrB).length();
		return temp2 * 1.0 / temp;
	}

	//第二种实现方式
	private static int compare(String str, String target) {
		int  d[][]; // 矩阵
		int  n = str.length();
		int  m = target.length();
		int  i; // 遍历str的
		int  j; // 遍历target的
		char ch1; // str的
		char ch2; // target的
		int  temp; // 记录相同字符,在某个矩阵位置值的增量,不是0就是1
		if (n == 0) {
			return m;
		}
		if (m == 0) {
			return n;
		}
		d = new int[n + 1][m + 1];
		for (i = 0; i <= n; i++) { // 初始化第一列
			d[i][0] = i;
		}

		for (j = 0; j <= m; j++) { // 初始化第一行
			d[0][j] = j;
		}

		for (i = 1; i <= n; i++) { // 遍历str
			ch1 = str.charAt(i - 1);
			// 去匹配target
			for (j = 1; j <= m; j++) {
				ch2 = target.charAt(j - 1);
				if (ch1 == ch2) {
					temp = 0;
				} else {
					temp = 1;
				}

				// 左边+1,上边+1, 左上角+temp取最小
				d[i][j] = min(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + temp);
			}
		}
		return d[n][m];
	}

	private static int min(int one, int two, int three) {
		return (one = one < two ? one : two) < three ? one : three;
	}

	/**
	 * 获取字符串的相似度
	 *
	 * @param str
	 * @param target
	 * @return
	 */
	public static double SimilarityRatio(String str, String target) {
		return 1 - (double) compare(str, target) / Math.max(str.length(), target.length());
	}


	/**
	 * 获取字符串编码
	 *
	 * @param str 需要处理的字符串
	 */
	public static String simpleEncoding(String str) {
		try {
			byte[] bs = str.getBytes(SysUtil.JVM_ENCODING);
			if (str.equals(new String(bs, CharsetUtil.UTF_8))) {
				return CharsetUtil.UTF_8;
			}
			if (str.equals(new String(bs, CharsetUtil.GBK))) {
				return CharsetUtil.GBK;
			}
			if (str.equals(new String(bs, "ISO-8859-1"))) {
				return "ISO-8859-1";
			}
		} catch (UnsupportedEncodingException e) {
			System.out.println("111111111");
			e.printStackTrace();
		}
		String encode = "GB2312";

		try {
			if (str.equals(new String(str.getBytes(encode), encode))) {
				return encode;
			}
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}

		encode = "ISO-8859-1";
		try {
			if (str.equals(new String(str.getBytes(encode), encode))) {
				return encode;
			}
		} catch (UnsupportedEncodingException exception1) {
			exception1.printStackTrace();
		}
		encode = "UTF-8";
		try {
			if (str.equals(new String(str.getBytes(encode), encode))) {
				return encode;
			}
		} catch (UnsupportedEncodingException exception1) {
			exception1.printStackTrace();
		}
		encode = "GBK";
		try {
			if (str.equals(new String(str.getBytes(encode), encode))) {
				return encode;

			}
		} catch (UnsupportedEncodingException exception1) {
			exception1.printStackTrace();
		}
		return "";
	}


}
